The purpose of the proposed study is to address the distinct need in epidemiologic studies for noninvasive, simple, but reliable methods for estimating body composition and patterning in elderly persons 65+ years of age. The term "body composition" refers to total body fat (TBF), the percent of weight that is fat (%BF), fat-free mass (FFM), total body water (TBW), and extra-cellular fluid (ECF). "Fat patterning" (FP) refers to the anatomical distribution of subcutaneous adipose tissue. Significant changes in body composition and fat patterning that have important health related effects occur with aging and knowledge of these changes is important for diagnoses, prognoses, and treatment of the elderly. There are few data, however, for body composition and fat patterning in the elderly because traditional methods have been difficult to apply for technical, conceptual or cost reasons. The proposed study will focus on the refinement of recumbent anthropometry, bioelectric impedance, and B-mode imaging ultrasound methods for estimating body composition and fat pattering that would be appropriate for epidemiologic studies. The underlying hypothesis of the study is that a combination of these methods can be used to estimate body composition and index fat patterning in the elderly in novel ways that circumvent factors, such as reduced mobility, that limit the application of conventional anthropometric and/or bioelectric impedance approaches. The first phase of the proposed research will involve the development and validation of methods for predicting body composition and fat pattern for a cross-sectional sample of 400 ambulatory, elderly men and women. The second phase will consist of the cross-validation of these methods using data from two independent samples.